Add pillar item to disable using upstart-based services

Fixes GH saltstack-formulas/nginx-formula#14.
Merge pull request #15 from tfolio/upstart-optional

Add pillar item to disable using upstart-based services
Adds basic ng state functionality.
Finishes vhost config template
Completes documentation for this first-pass.
More documentation touches.
Merge pull request #18 from spsoit/master

Adds NG states
Changed README to emphasize the differences with the "ng" states
Added missing TOC for the ng states
Tightened up some requirements.
Merge pull request #19 from spsoit/master

Tightened up some ng requisites.
Adjusts the parameters passed to context to be passed as json and hopefully avoid double quoting. Also brings indentation in-line with salt doc 23.14.1.2.1
Merge pull request #20 from spsoit/master

Context parameter safety fixes
Fixed minor typo in nginx.ng.config.sls
add support for worker_rlimit_nofile
add support for events { use <epoll,etc>}
suppress newlines
remove extra curly
Merge pull request #21 from TaiSHiNet/master

Fixed minor typo in nginx.ng.config.sls
set 'daemon on;' by default